[be5invis]

I don't see any references to things like HarfBuzz or DWRITE, which are NECESSARY to properly display any scripts that's not European. All properly implemented text editors are rich text — because you will need to support font fallback and BiDi and all the Unicode complexity

[coldtea]

You absolutely don't need any of these for a tutorial text editor... Those are all things you can hook-in later, after you've understood how to make text editors...

[kbsletten]

Did you see that this is a command line app (like VI, or EMACS)? Those libraries look like they're used for GUIs. Do you know if they can be used for the terminal?